1. Field of the Invention
The present invention relates to a coating and developing treatment system and a coating and developing treatment method for a substrate.
2. Description of the Related Art
In photolithography of the process of fabricating a semiconductor device, for example, resist coating treatment for forming a resist film on the surface of a wafer, developing treatment for developing the wafer after pattern exposure, heat treatment and cooling treatment performed before the coating treatment, before and after exposure processing, and after the developing treatment, and the like are performed. Such treatment and processing are performed in treatment units provided individually, and these treatment units are unified as a coating and developing treatment system so as to continuously perform the aforesaid successive treatment and processing. The exposure processing of a pattern is usually performed in an exposure processing unit(aligner) disposed adjacent to the coating and developing treatment system.
Generally, the coating and developing treatment system is composed of a loader and unloader section for carrying the wafer in/out of the coating and developing treatment system, a treatment section having a coating treatment unit, a developing treatment unit, a thermal treatment unit, and the like and performing the majority of the aforesaid treatment of the wafer, and an interface section for delivering the wafer between the treatment section and an exposure processing unit provided outside the system.
When the wafer is treated in this coating and developing treatment system, air cleaned by an air cleaner or the like is supplied as down-flowing air into the coating and developing treatment system in order to prevent impurities such as particulates from adhering to the wafer, while an atmosphere in the coating and developing treatment system is exhausted, whereby the wafer can be treated in a clean condition.
In recent years, however, exposure technology in which a beam with a shorter wavelength (for example, 157 nm) is used is being developed to form a finer and more precise circuit pattern. When the beam with the short wavelength is used, there is a fear that even impurities at molecular level such as oxygen, ozone, and water vapor which have been insignificant so far exert a bad influence on exposure processing, whereby a precise circuit pattern is not formed.
Hence, when at least the wafer is subjected to exposure processing, it is required that no impurities such as oxygen adhere onto the wafer. If only clean air is supplied as in prior arts, the adhesion of impurities onto the wafer can not be suppressed effectively since impurities such as oxygen are contained in the air, and moreover impurities adhering onto the wafer can not be removed.
The present invention is made in view of such a point, and its object is to remove impurities at molecular level such as oxygen adhering to a substrate such as a wafer in a coating and developing treatment system and a coating and developing treatment method.
To attain this object, according to a first aspect of the present invention, the present invention is a coating and developing treatment system for performing coating and developing treatment for a substrate, comprising: a treatment section having a coating treatment unit for forming a coating film on the substrate, a developing treatment unit for developing the substrate, a thermal treatment unit for performing thermal treatment for the substrate, and a first carrier unit for carrying the substrate into/out of these coating treatment unit, developing treatment unit, and thermal treatment unit; an interface section having a second carrier unit for carrying the substrate through a route at least between the treatment section and an exposure processing unit provided outside the system for performing exposure processing for the substrate; and a pressure reducing and removing unit for removing impurities adhering to the coating film on the substrate by suction in a chamber before the substrate is subjected to the exposure processing.
Incidentally, the second carrier unit needs to only gave a function of carrying the substrate into/out of the treatment section, and need not have a function of carrying the substrate into/out of the exposure processing unit provided outside the system. In addition to particulates such as dust, impurities at molecular level such as oxygen, ozone, water vapor, and organic substances are also included in the aforesaid impurities.
According to another aspect of the present invention, the present invention is a coating and developing treatment system for performing coating and developing treatment for a substrate, comprising: a treatment section having a coating treatment unit for forming a coating form on the substrate, a developing treatment unit for developing the substrate, a thermal treatment unit for performing thermal treatment for the substrate, and a first carrier unit for carrying the substrate into/out of these coating treatment unit, developing treatment unit, and thermal treatment unit; an interface section having a second carrier unit for carrying the substrate through a route at least between the treatment section and an exposure processing unit provided outside the system for performing exposure processing for the substrate; a delivery section which is connected between the interface section and the exposure processing unit and hermetically closeable; and a pressure reducing unit for reducing a pressure in the delivery section to a predetermined set pressure.
According to still another aspect of the present invention, a coating and developing treatment method of the present invention is a method for performing coating and developing treatment to a substrate, comprising the steps of: supplying a coating solution to the substrate to form a coating film on the substrate; exposing the substrate by irradiating a predetermined beam to the substrate on which the coating film is formed; developing the substrate after the exposure processing; removing impurities adhering to the substrate from the substrate between the step of forming the coating film and the step of exposing the substrate.
According to the present invention, the impurities adhering to the coating film on the substrate are removed by the pressure reducing and removing unit, whereby exposure processing of the substrate is performed suitably without being influenced by the impurities. Accordingly, even if exposure is performed with a beam having a short wavelength of 157 nm or less, for example, there is no possibility that any defect occurs to the substrate after exposure. Although it is thought that a clean atmosphere is always maintained in the vicinity of the substrate in order to prevent impurities from adhering to the substrate, it is difficult to produce an atmosphere from which oxygen and water vapor at molecular level are removed completely, and thus there is a limit to the prevention of adhesion of impurities. Hence, it is more practical and effective to provide a unit capable of removing impurities which has already adhered as in the present invention. The position of the pressure reducing and removing unit may be inside the coating and developing treatment system or may be outside the coating and developing treatment system. Moreover, since a solvent in a treatment solution can be also vaporized simultaneously in the pressure reducing and removing unit, it is also possible to simultaneously perform such vaporization treatment which has been hitherto performed by heating.
According to the present invention, the delivery section which is connected between the interface section and the exposure processing unit and is hermetically closeable and the pressure reducing unit for reducing the pressure in the delivery section are provided, whereby the substrate passes through the delivery section before exposure processing at which time the pressure in the delivery section can be reduced. If the pressure in the delivery section is reduced, impurities at molecular level such as oxygen adhering to the surface of the substrate can be detached from the substrate and removed. As a result, exposure processing thereafter can be performed suitably without being adversely affected by the impurities. Hence, even if exposure is performed with a beam having a short wavelength of 157 nm or less, for example, there is no possibility that any defect occurs to the substrate after exposure. Moreover, since the solvent in the treatment solution can be also vaporized simultaneously, it is also possible to simultaneously perform such vaporization treatment which has been hitherto performed by heating.